468 SUMMAEY OF GUREENT BESEARCHES RELATING TO 



the ijlants employed being the stmflower, pumpldii, turnip, and 

 tobacco. To isolate the chloropliyll (not separating the yellow and 

 green pigments), he first boiled for a short time in water, and then 

 extracted the chlorophyll by hot 96 per cent, alcohol. After saponi- 

 fying the alcoholic solution, the pigment was extracted by alcohol- 

 ether, evaporated, dried, and weighed. The results varied considerably 

 with the species, but gave an average of 5 • 142 gr. to 1 sq. metre of 

 surface. Comparing this with Sachs's statement that in favourable 

 weather 1-6 gr. of starch are formed per hour per sq. m. (in the sun- 

 flower and pumpkin), it follows that 0-2 gr. of the chlorophyll- 

 p)igment are employed in the production of I'O gr. of starch. Dr. 

 Hansen believes that the chlorophyll-pigment acts as the carrier of 

 carbon dioxide to the assimilating protoplasm in the chlorophyll- 

 grains. 



Chlorophyll and the reduction of Carbonic Acid.* — By treating 

 an alcoholic solution of chlorophyll with nascent hydrogen, M. C 

 Timiriazeff obtained a substance, which was yellow in dilute, and red 

 in concentrated solutions. The spectrum of this substance showed 

 a marked difference from that of chlorophyll ; the line I in the red 

 was absent, and a large band was present, extending some distance on 

 each side of the position of line II of the chlorophyll spectrum. 

 This substance rapidly becomes oxidized in contact with air, and 

 turns green. The band I reappears in the spectrum when the 

 slightest trace of oxygen is present. 



The author gives the name " protochlorophylline " or "proto- 

 phylline " to this substance, which he regards as a product of 

 reduction of the green principle of chlorophyll, which he has ali-eady 

 named " chlorophylline." Solutions of this substance, in sealed tubes 

 with carbonic acid, retain their characteristics in the dark, but in sun- 

 light rapidly become green, being converted into chlorophyll. The 

 author is inclined to consider that the reduction of chlorophyll in 

 living plants takes place apart from the plant itself, and that chloro- 

 phyll is formed by oxidation at the expense of carbonic acid. He 

 considers that this " protophylline " exists in the living plant, and 

 that the difference between the spectrum of freshly extracted chloro- 

 phyll, and that which has undergone oxidation is due to the presence 

 of this " protophylline." Moreover, protophylline is only a stage in 

 the reduction ; for if a mineral acid or an excess of carbonic acid be 

 present under the described conditions, a complete destruction of 

 colouring matter takes place. He expects that the study of these 

 substances in the normal and etiolated state of living plants will 

 throw a light on the chemical side of the action of chlorophyll, which 

 has lately been studied only physically. 



Action of Chlorophyll in the TTltra-Violet Obscurity-t— MM. 

 G. Bonnier and L. Mangin show that, in opposition to the ordinarily 

 receiyed doctrine that the action of chlorophyll (the absorption of 



• Comptes Eendus, cii. (1886) pp. 686-9. Cf. this Journal, v. (1885) p. 837, 

 ante, p. 281. 



t Comptes Eendus, cii. (188G) pp. 123-6. 



